Merc 60HP EFI 4 Stroke

Been watching the summer session pass before my eyes. Dry docked with engine trouble sure does bite. Looking for any suggestions, tips, hints, or tricks.

Boat = Tracker Pro V16.

Motor = 60HP 4 stroke EFI Merc

Boat & Motor 2006MY.

Symptom(s): Topping out at 4K RPM. Gas in the oil.

In the past I could pile 5 people + gear. Little slow out of the hole but would top out around 30mph between 5600 & 5800 RPM. The inner liner on the gas line (tank to motor) shattered over the winter months in cold storage. Replaced the line. Tore out the infested factory fuel filter and installed an in-line. Cleaned the fuel line to and from the pump as well as soaked the injectors. Ran great for a couple outtings. But back to the same symptom (RPM) with the addition of gas getting into the oil. I’m not for sure on the time line with the gas in the oil. Only thing I can tell you is late last Fall when I changed the oil ~ there was NO gas in it. I replaced the thermostat thinking she might me running too cold and checked the fuel tank vent. No change in symptoms. The fuel filter is as clean as a whistle. If I disconnect the injectors electrically one at time the alarm trips and motor begins to cut out. Injectors appear to be working. I’m pretty confident I don’t have a lingering fuel system issue ~ other than gas getting into the oil. She idles fine and fast idles fine. No unusual motor noises or metal on metal. There is a little bit of vibration pending tilt position.

12 pitch AL prop with the same ding on one blade that I had last year when she ran fine. Visually ~ the prop looks fine but I know it doesn’t take much. I’m not sure a prop issue would lead to gas getting by the rings. Most logic answer for gas in the oil is a fuel pump issue. But would I get good pressure at the injectors if the fuel pump was the culprit?

Short of taking to an authorized dealer to pull codes ~ anybody have any suggestions? Am I over looking something simple here?

I’m gonna go ahead and replace the prop this weekend to eliminate that as a possibility.

Forget to mention ~ replaced the plugs already. No change. Plug wires are okay according to mr ohm meter.

did u hit something?? maybe the prop shaft got bent and it’s not just the prop…i’m not an expert just an idea

not sure how the fuel pump would be related to fuel in the oil?? Sounds like a leaking injector to me or the puter is telling it to dump in too much fuel. I would lean towards injector since those were worked with. Fuel in the gas should show on a plug which cylinder it is coming from. This is where I would start.

I had a 60horse Yamaha that would get gas in oil. It ran great and never had any other problems. The gas would not show up all the time. I took it in and had a fuel pump put on and never had it happen again.

Follow up.
Yesterday I took the fuel pump apart. Everything looked good. Great spring reaction on the piston.
Dropped it in the water and topped out at 4k (same ole same ole). Decided to run it for a bit. About an hour into the run ~ it was as if somebody flipped a switch. Just like that ~ she took off. 5.8k ~ where I should be! Either I had a piece of debris in the bottom injector that finally blew thru OR it’s a temperature related issue. We’ll find out soon enough if injector debris was the culprit.
Oh….and no gas in the latest batch of oil. Ran it for 6 hours yesterday from one end of pool 9 to the next.

not sure about the efi on that motor but cars run in choke mode until they are up to temp, maybe the t-stat was stuck open and it wasn’t warming up (seems like a long shot)???? I would lean towards an injector had something in it. Hopefully it’s fixed and doesn’t come back. good luck

It won’t ‘make oil’ when the engine is warm enough to open the thermostat. It does it when trolling or slow going in cold temps.It’s unburnt fuel going into the crankcase by way of the rings due to the rings not being seated properly.
Been told the best fix is to run hard at full throttle at or near max rpms for 1 hour to seat the rings. But don’t run over 6000rpm.
I have the same motor.

After Saturday’s turn of events I was hopeful the bottom injector’s fuel path was merely compromised and blew free. Unfortunately that’s not it. Dropped it in the water yesterday and experienced similar results. 4k tops. About as depressing as a Kebler elf being demoted to fudge packer.

Gotta be something related to ambient temperature.
I ran….I mean “putted” up to the north end of the Bay. Shut’er down & dropped the trolling motor. Trolled around throwing a red/white (in honor of Independance Day) spinner. Three pike 24″ to 28″ got to meet the Frabil with two more blow ups I whiffed on. With a little less than hour elapsed fishing I ran out of submerged vegitation to fish without doubling back. Started the motor and with the drop of the throttle ~ BOOYAH! 5.8k back to normality!

So………..after about an hour of sitting in the beating sun with ambient temps above 85 degrees she took right off. I already replaced the t-stat so chances are relatively low that is the problem. But this is the second time it’s took off after being exposed to 85+ ambient temps for an extended period of time in the water. It’s funny too because the throttle “feels” totally different. Loose and limber as compared to stiff and bogged down. Gonna take it Starks on Thursday and see what Chuck and the boys can decipher.

#4 coil was in failure mode. Pure coincidence on the ambient temp thing. Replaced it yesterday. She ran great last night.